A keyboard is one of the widely-used computer peripheral devices. Via the keyboard, the user may input characters or commands into a computer. With increasing development of science and technology, the keyboard manufacturers make efforts in designing novel keyboards with diversified functions in order to meet the requirements of different users. Recently, an illuminated keyboard with an illuminating function has been introduced into the market. Consequently, in a case that the illuminated keyboard is used in the dim environment with insufficient luminance, the characters marked on the keys of the illuminated keyboard are still clearly visible to the user.
Hereinafter, the structure of a conventional illuminated keyboard will be illustrated with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view illustrating a conventional illuminated keyboard.
Firstly, the components of the conventional illuminated keyboard are described. As shown in FIG. 1, the conventional illuminated keyboard 1 comprises at least one key 11, a membrane switch circuit module 12, a base plate 13, and a backlight module 14.
The key 11 comprises a keycap 111, an upward/downward supporting member 112 and an elastic element 113. Moreover, the membrane switch circuit module 12 comprises an upper wiring plate 121 and a lower wiring plate 122. An upper contact 121a is formed on the upper wiring plate 121. Corresponding to the upper contact 121a, a lower contact 122a is formed on the lower wiring plate 122. Moreover, the backlight module 14 comprises a light guide plate 141, a reflective plate 142 and a light-emitting element 143.
The operating principle of the key 11 of the conventional illuminated keyboard 1 will be illustrated in more details as follows. Firstly, the upward/downward supporting member 112 of the key 11 is connected with the keycap 111 and the base plate 13. The elastic element 113 is disposed within the upward/downward supporting member 112, and arranged between the keycap 111 and the base plate 13. The membrane switch circuit module 12 is arranged between the elastic element 113 and the base plate 13.
As the key 11 is depressed, the keycap 111 is correspondingly moved with the upward/downward supporting member 112 in a vertical direction toward the base plate 13, and the membrane switch circuit module 12 is pushed by a protrusion part 113a within the elastic element 113. Under this circumstance, the upper contact 121a and the lower contact 122a of the membrane switch circuit module 12 are contacted with each other to be electrically conducted. Consequently, a corresponding input function is executed.
The illuminating principles of the conventional illuminated keyboard 1 will be illustrated as follows. Firstly, the light guide plate 141 is disposed under the base plate 13, and the reflective plate 142 is disposed under the light guide plate 141. The light-emitting element 143 is located at a side of the light guide plate 141. The light-emitting element 143 may emit a light beam. The light beam is introduced into the light guide plate 141 and guided by the light guide plate 141. Moreover, the light beam emitted by the light-emitting element 143 is reflected by the reflective plate 142, so that the light beam is transferred within the light guide plate 141 more uniformly. Moreover, a portion of the light beam is projected upwardly through a base plate opening 131 of the base plate and a light-transmissible part of the keycap 111 so as to result in the illuminating efficacy.
From the above, the key 11 of the conventional illuminated keyboard 1 is selectively illuminated by controlling the on/off states of the light-emitting element 143. In other words, it is inconvenient for the user to manually turn on or turn off the light-emitting element 143. In case that a complicated circuitry and a sensing device are installed in the conventional illuminated keyboard 1, the light-emitting element 143 may be automatically turned on or turned off during the period of using the illuminated keyboard 1. However, the additional design of the complicated circuitry and the sensing device may increase the fabricating cost and the process complexity. Moreover, for changing the color of the light beam, it is necessary to employ another light source to emit the corresponding color light. Under this circumstance, the fabricating cost is further increased.
Therefore, there is a need of providing an improved illuminated keyboard in order to overcome the above drawbacks.